1. Field of the Invention
This invention pertains to differential systems for motor vehicles and, more particularly, the invention pertains to a method for controlling an axle shaft endplay in a differential assembly.
2. Description of the Prior Art
In conventional drivelines, particularly those for rear wheel drive vehicles, the left-hand and right-hand axle shafts extend laterally from a differential mechanism that includes side bevel gears in continuous meshing engagement with differential pinions supported rotatably on a pinion shaft carried on a differential carrier. The differential carrier is driven rotatably by a set of meshing bevel gears, one of which is driven by a drive shaft disposed substantially perpendicular to the axle shafts. The side bevel gears typically are connected rotatably to the axle shafts by a spline connection formed on a shoulder near the inboard ends of the axle shafts. Each axle shaft carries another shoulder at its axially innermost extremity, the second shoulder located adjacent the differential pinion shaft.
Located between the shoulders on the axle shaft is an annular recess that is axially aligned with the recess formed on the corresponding side bevel gear. A slotted washer or retainer ring, fitted within the recesses of the axle shaft and side bevel gear, limits outward axial movement of the axle shaft relative to the side bevel gear. However, each axle shaft is free to move along the spline connection axially inward toward the differential pinion shaft. This amount of an internal axial clearance is called an axle shaft endplay.
The excessive amount of the endplay in the differential assemblies allows the axle shafts to shift axially inwardly relative to the differential case and jar or knock against the pinion shaft. Moreover, the conventional assembly can lead to grinding away of the end of the side yoke causing excessive negative camber, which in turn can lead to uneven tire wear and poor driving stability. It can also cause particles of the side yokes to embed themselves in the differential clutch plates causing slippage of the differential unit resulting in a clunking or thumping noise. If the wear is left unchecked, it may increase to a point where the flange will shear or cut into the differential case causing a leakage of fluid and ultimately leading to complete destruction of the differential assembly.
The current retention method of the axle shaft does not allow an endplay control. Therefore, the need exists to control the endplay of the axle shaft in order to provide a predetermined desired endplay in accordance with vehicle manufacturer""s specification and/or depending on the operational conditions of the axle assembly.
It is an object of the present invention to provide a method for controlling an axial displacement of an axle shaft in a differential assembly.
The method, according to the present invention, for controlling an axle shaft endplay in a differential assembly is preformed in the following manner: first, a value of a desired endplay xcex4=xcex4p is determined based on particular operational conditions and the type of the differential assembly. A differential mechanism is partially assembled including side gears and a pinion shaft carrying bevel pinion gears in continuous meshing engagement with the side gears in a differential case. Then, a thickness WR of the axle shaft retaining ring is calculated that would provide the desired endplay xcex4p. In accordance with the present invention, the manufacturer of the axle assemblies is provided with an endplay controlling kit that includes a plurality of the axle shaft retaining rings of assorted thickness. The appropriate retaining ring having the determined thickness WR calculated during the previous step of the present method, is selected from the plurality of the assorted retaining rings of the endplay controlling kit. Next, the axle shaft is inserted into the differential case through the side gear, and the selected retaining ring is mounted to the axle shaft. Finally, remaining components of the differential assembly are assembled, thus, completing the process of assembling the differential assembly. The plurality of the axle shaft retaining rings in the endplay controlling kit have the thickness ranging from a thinnest having the thickness WRmin to the thickest having the thickness WRmax. The thinner retainer rings provide more endplay, and the thicker retainer rings provide less endplay. Also, the differential assembly with a zero axle endplay may be provided.
Therefore, the present method for controlling the endplay of the axle shaft solves the need for a solution to the problem of controlling the axle shaft endplay in the vehicular differential assemblies in a simple, efficient and inexpensive manner.
These and other benefits of the present invention will become apparent from the following description and associated drawings.